Knowledge Resource Center for Ecological Environment in Arid Area
| 黄旗海湖积物中有机质及有机碳同位素古气候意义的研究 | |
| 王小燕 | |
| 出版年 | 2000 |
| 学位类型 | 硕士 |
| 导师 | 余俊清 |
| 学位授予单位 | 中国科学院青海盐湖研究所 |
| 中文摘要 | 分布在不同气候带和生态环境中的各类湖泊是人类观察和了解过去全球变化，预测未来生态环境发展趋势的重要窗口。近年来，湖泊沉积有机质稳定碳同位素(δ~(13)C_(org))用于获取区域气候与环境变化信息方面的研究在国内外发展迅速，成果令人瞩目。保存在各类湖泊岩芯中的δ~(13)C_(org)记录揭示了晚更新世以来大气C0_2浓度的变化，湖泊水位波动，湖区生态与植被的变迁，以及地区温度变化等环境信息。我们从内蒙察右前旗的黄旗海湖泊中央深水区钻取了三个各长十一米的岩\n芯柱，对它们的多学科综合测试和研究工作正在进行之中。本文侧重侧告对HQH4孔芯的部分研究成果。通过研究该孔岩芯的有机质(OM)含量和δ‰，探讨了半干旱区浅水封闭型湖泊沉积物中δ~(13)C_(org)和OM记录与冰后期以来气候与环境变迁的关联。研究结果表明，黄旗海湖区在全新世到来之前的气候较寒冷和干燥，湖泊有机生产率比全新世要低很多(有机质含量比全新世低十三倍)。与此相对应，δ~(13)C_(org)值比全新世平均要高2.77‰。此外，整个沉积岩芯剖面中δ‰与OM呈现较好的负相关关系(负相关系数r = O.782)。初步判定，黄旗海湖泊有机生\n产率在全新世初的显著攀升很可能由于当时的区域气候急剧变暖造成湖泊营养水平迅速提高所致。相应δ~(13)C_(org)的降低很大程度上与有机产率的增高有直接的关系。而δ~(13)C_(org)值在全新世期间相对-26.4‰同位素均值的正负偏移主要反映该湖有机质生产率和保存条件的变化。这种变化则与当时的气候，尤其是湖水水位的波动有直接关联。放射性碳年代学测定工作目前正在进行之中。本文根据该孔沉积纹层计年法，获得了黄旗海湖泊全新世平均沉积速率为0.805 mm/年。根据以上研究结果及沉积岩性地层学，对黄旗海冰后期气候与环境演变的主要阶段作了划分，并与前人湖岸沉积剖面的研究结果以及北欧冰后期气候划分作了初步对比和讨论。 |
| 英文摘要 | Diverse lakes distributed in different climatic zones and ecological environments archived\nmuch useful infformation on environmental changes for the study of past global changes and for the understanding and prediction of possible trends of the changing environments in which now we are living. In the past two decades, organic carbon isotopic records from lake sediment cores were increasingly studied and used as a valuable environmental proxy indicating glacial-interglacial change in atmospheric pCO_2, major fluctuations in catchment vegetation, and changes \nin lake-level and regional temperature. We have successfully recovered three sediment cores of 11 m long each from the middle of Lake Huangqihai, Inner Mongolia. A multi-proxy approach was applied to the study of cores. In this thesis study, we report results from investigation on the records of organic matter (OM) and organic carbon isotope (δ~(13)C_(org)) from core HQH4 and discuss environmental implications of the two proxies from the shallow closed-drainage lake. Results suggest that the pre-Holocene climate at Lake Huangqihai was cold and dry, as evidenced by the organic productivity distinctly lower than the Holocene (OM content is on average 13 times lower). Correspondingly, the δ~(13)C_(org) values of the pre-Holocene sediments are on \naverage 2.77‰ higher than the Holocene. In addition, δ13Corg values from core HQH4 inversely correlate well with OM contents (r = 0.782). About 2%0 negative shift in δ~(13)C_(org) around the late glacial/Holocene boundary is in a way related to rapid increase in the organic productivity of the palco-lake. The substantial increase in primary productivity at the onset of the Holocene in Lake Hnangqihai provides evidence for an abrupt warming at that time of the regional climate. Variation in δ~(13)C_(org) during the Holocene is characterized by both negative and positive \nexcursions from the line of the average δ~(13)C_(org) value of-26.4‰. These excursions may principally reflect the magnitude, timing and duration of certain conditions in productivity and OM preservation, which in some way link to climate-induced lake-level fluctuations. While age data from the ongoing radiocarbon measurements is yet not available, varve counting for the Holocene sediments of core HQH4 provides an average sedimentation rate of 0.805 mm/year. Based on the data available, as presented above, environmental stages from the post-glacial lacustrine sequence thus are distinguished. An attempt was made to correlate these stages with those from Northern Europe and from the sediment sections around shore area of Lake Huangqihai. |
| 中文关键词 | 黄旗海湖 ; 湖底岩芯 ; 有机质 ; 碳同位素 ; 冰后期气候变化 |
| 英文关键词 | lake huangqihai sediment cores organic matter carbon isotope post-glacial climatic change |
| 语种 | 中文 |
| 国家 | 中国 |
| 来源机构 | 中国科学院青海盐湖研究所 |
| 资源类型 | 学位论文 |
| 条目标识符 | http://119.78.100.177/qdio/handle/2XILL650/286252 |
| 推荐引用方式 GB/T 7714 | 王小燕. 黄旗海湖积物中有机质及有机碳同位素古气候意义的研究[D]. 中国科学院青海盐湖研究所,2000. |
| 条目包含的文件 | 条目无相关文件。 | |||||
| 个性服务 |
| 推荐该条目 |
| 保存到收藏夹 |
| 导出为Endnote文件 |
| 谷歌学术 |
| 谷歌学术中相似的文章 |
| [王小燕]的文章 |
| 百度学术 |
| 百度学术中相似的文章 |
| [王小燕]的文章 |
| 必应学术 |
| 必应学术中相似的文章 |
| [王小燕]的文章 |
| 相关权益政策 |
| 暂无数据 |
| 收藏/分享 |
除非特别说明，本系统中所有内容都受版权保护，并保留所有权利。
